The present invention relates to closure members for containers, bottles and the like and, more particularly, to closure members having indicator means to indicate the number of times the container has been opened. The invention can also be used for any other application in which the number of times a given activity is performed must be indicated.
In the medical field, medical drugs have a predetermined therapeutic range in which the effects of taking the drug are beneficial. Under-utilization of a drug may endanger the user with the drug's side effects without reaching levels necessary for a therapeutic action. On the other hand, over-utilization may cause side effects or toxicity to a much greater extent than any possible benefit. Thus it is critically important that a patient follow prescribed directions on medications, yet frequently patients forget whether they have taken medication and either omit doses or repeat them.
A considerable number of pill-timing schemes have been used to solve the problem of reminding a patient to take a dose of medicine or reminding him he has already taken the dose. The most used ones involve some scheme of compartmentalization of the necessary medication, such that the pills are placed in compartments that are labeled by day, dose number of time of day, or that are serially numbered. These devices are reasonably satisfactory if a responsible person is available and has the time and patience to fill the compartments properly.
In dispensing pills of a single type, a number of window-containing bottle caps have been invented. Through the window a movable element marked with an index is visible. In only a few devices does the indicating element index in position relative to the window each time the cap is loosened, removed, replaced, and retightened. Thus, by looking at the index mark displayed through the window, a user can see where in repetitive sequence of dose he or she is.
One of the most serious disadvantages of prior art devices of the window indexing type is that there is no warning to the user in case the user does not turn the device far enough during the opening or closing to properly advance the window. Unless the user is alert to the index value before opening and then after closing such devices, the user will be unaware that the window failed to advance to a new index. Most users, especially the elderly who may not understand how the device operates, will not be this alert to the functioning of the device. In addition, most prior art devices fail to provide positive locking in both directions of movement; thus, the index may be moved appropriately when the device is opened or closed, but additional movement is not prevented when the device is moved in the opposite direction. This allows the index to drift, often causing failure or an incorrect reading, particularly after the device has been used over a period of time.
The device of U.S. Pat. No. 4,011,829 issued Mar. 15, 1977 to Wachsmann, et al., attempts to provide positive locking in both directions, but because of the direction of the tooth designed to prevent movement of the index upon closure, the device may not work reliably, particularly after wearing with use. Also, the device of Wachsmann does not provide space for the ratchet teeth to slide past the engagement teeth when the device is moving in a direction wherein such teeth should disengage, which may cause unreliable operation over a period of time. Another drawback of this device is its inclusion of a complicated "child proofing" feature with the indexing feature, which makes the device quite complex. Other features of this device, such as the method of providing the lost motion drive and the requirement of a post in the middle of the elements to hold the device together, also increase its complexity.
The device of U.S. Pat. No. 3,151,599 issued Oct. 6, 1964 to Livingston provides positive locking in both directions, but it does so by means of very closely spaced projections that would be difficult to manufacture economically. Furthermore, this device does not provide space for the projections to move while sliding past each other when not engaged.
The device of U.S. Pat. No. 4,666,051 issued May 19, 1987 to Trick has an indicator wheel with a serrated rim projecting above and below the plane of the wheel. The serrations engage mating serrations in upper and lower elements in order to drive the indicator mechanism. The serrations are rigid and, therefore, tend to wear excessively as they slide past one another.
It is also apparent from a review of this art that there is a need for an improved indicator cap that can be used as a child-resistent closure. Preferably, such a cap would have a minimum of parts, would be easily manufactured and assembled using standard injection molding and assembly methods, and could be used with ordinary containers that are not necessarily specially designed for the cap.
It is also apparent from a review of this art that the prior art devices are generally designed for attachment to a container of a particular size. For example, the Wachsmann device is a cap with indicating features that is designed with threads that fit into a particular threaded container. Other devices may include a skirt portion on the outer shell of the device that fits over a standard cap of a container so that the standard cap nests inside the skirt. Yet other devices may be substantially disk-shaped so that they can be attached directly to the top of a standard cap. The cap is removed from the container by grasping the device and turning it along with the standard cap to which it is attached, thereby advancing the indicator mechanism. In the case of these last two types of devices, the devices cannot be used effectively with standard caps that are too large. In the device with the skirt, a large standard cap will not rest into the skirt. In the disk-shaped device that is attached to the top of a standard cap, the device will be too small in relation to the cap to be gripped effectively and, instead, the user will inadvertently grip the standard cap itself so that the indicator mechanism is not advanced.